/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.queryengine.plan.relational.analyzer;

import java.util.Objects;

import static com.google.common.base.MoreObjects.toStringHelper;
import static com.google.common.base.Preconditions.checkArgument;
import static java.util.Objects.requireNonNull;

public final class FieldId {
  public static FieldId from(ResolvedField field) {
    requireNonNull(field, "field is null");

    Scope sourceScope = field.getScope();
    RelationType relationType = sourceScope.getRelationType();
    return new FieldId(sourceScope.getRelationId(), relationType.indexOf(field.getField()));
  }

  private final RelationId relationId;
  private final int fieldIndex;

  public FieldId(RelationId relationId, int fieldIndex) {
    this.relationId = requireNonNull(relationId, "relationId is null");

    checkArgument(fieldIndex >= 0, "fieldIndex must be non-negative, got: %s", fieldIndex);
    this.fieldIndex = fieldIndex;
  }

  public RelationId getRelationId() {
    return relationId;
  }

  /**
   * Returns {@link RelationType#indexOf(Field) field index} of the field in the containing
   * relation.
   */
  public int getFieldIndex() {
    return fieldIndex;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    FieldId fieldId = (FieldId) o;
    return fieldIndex == fieldId.fieldIndex && Objects.equals(relationId, fieldId.relationId);
  }

  @Override
  public int hashCode() {
    return Objects.hash(relationId, fieldIndex);
  }

  @Override
  public String toString() {
    return toStringHelper(this).addValue(relationId).addValue(fieldIndex).toString();
  }
}
